1. Field of the Invention
This invention relates to a tilting device and, more particularly, to a tilting device that makes it possible to tilt around at least one axis.
2. Description of Relevant Art
Such tilting arrangements are well known in the art. They serve to deflect a light beam incident on them through a given angle. There is a differentiation, in particular, between 1-axis and 2-axis tilting mirrors.
While single-axis tilting mirrors are today commercially available with great technical variety, two-axis tilting mirrors, which are today indeed state of the art and on the market, are subject to important technical limitations.
A tilting mirror arrangement used for scanning is known from U.S. Pat. No. 4,708,420. In it, the scanning mirror is connected via flexible joints to piezoceramic drive elements arranged parallel to the mirror surface. This arrangement has to be very large so that the piezoceramic drive elements can tilt the mirror through a large angle. This results from the small deflection of the piezoceramic drive elements, which is proportional to the length of these elements. This arrangement is thus not suited to tilt small mirrors through a large angular range, when the drive mechanism behind the tilting mirror is to be limited to the dimensions of the mirror surface.
In a tilting mirror arrangement known from U.S. Pat. No. 4,383,763, the mirror is mounted at one point and is moved by piezoelectric ceramics. Here also, the dimensions of the mirror have to be very large if the tilting mirror is to be tilted through at least 1.degree..
A tilting mirror mounting is known from U.S. Pat. No. 4,660,941, in which the movement of the tilting mirror is effected by piezoelectric elements that act on the mirror via levers. This arrangement is also not suitable for tilting a small mirror through at least 1.degree..
A piezoelectric beam reflector is known from U.S. Pat. No. 5,170,277, in which the mirror member is directly attached to the piezoelectric element. This has the disadvantage that the mirror has no defined pivot point when pivoting.
A piezoelectric beam reflector is known from U.S. Pat. No. 4,691,212, and is used in a scanning arrangement. The disadvantage of this arrangement is that a given deflection angle cannot be rigidly maintained when the pivot point is to remain stationary.
A piezoelectric scanning device is known from German Patent DE 195 19 161, in which a pair of piezoelectric plate elements, which extend transversely of a base, act in common on a constructional element at one end such that this constructional element tilts. Thus, for one tilt axis, two plate elements that move together are necessary, and have to move oppositely for tilting. The plate elements engage for this purpose at different places on a bar beneath the constructional element. Two additional plate elements are required for tilting around a tilt axis perpendicular to this.